package Arraylist;


import java.util.Queue;

/**
 * 设计循环队列
 */
class MyCircularQueue {
    public int[] elem;
    public int front;
    public int rear;

    public MyCircularQueue(int k) {
        this.elem = new int[k+1];
    }

    /**
     * 入队
     * @param value
     * @return
     */
    public boolean enQueue(int value) {
        if(isFull()) {
            return false;
        }
        elem[rear] = value;
        rear = (rear+1) % elem.length;

        return true;
    }

    /**
     * 出队
     * @return
     */
    public boolean deQueue() {
        if(isEmpty()) {
            return false;
        }

        elem[front] = 0;
        front = (front+1) % elem.length;
        return true;
    }

    /**
     * 拿队头元素
     * @return
     */
    public int Front() {
        if(isEmpty()) {
            return -1;
        }
        int ret = elem[front];
        return ret;
    }
    
    public int Rear() {
        if(isEmpty()) {
            return -1;
        }

        int index = (rear == 0) ? (elem.length - 1) : (rear - 1);

        return elem[index];
    }
    
    public boolean isEmpty() {
        return front == rear;
    }
    
    public boolean isFull() {
        return (rear+1) % elem.length == front;
    }
}